NIOSH has identified agricultural workers and Hispanic and foreign-born (i.e., immigrant) workers as special populations due to their high risk of occupational injuries and illnesses. Agriculture has become the most hazardous occupational sector in the United States. Across occupations, foreign-born workers have experienced increasing occupational fatality rates in recent years, even as the overall occupational fatality rate has declined. Undocumented immigrants are hypothesized to be particularly vulnerable to occupational injuries and illnesses, but due to limited availability of data which distinguishes legal immigration status, little empirical research has addressed this hypothesis. Undocumented immigrants are also hypothesized to be less likely to report their workplace injuries or illnesses to their employers, posing challenges to surveillance efforts. If undocumented workers are both more likely to be injured at work and less likely to report such injuries, this may render the dangerous conditions at their workplaces invisible to existing surveillance efforts and impede effective targeting of interventions to improve workplace safety. Direct surveys of workers have the potential to improve surveillance, and NIOSH has partnered with DOL to field Occupational Health and Occupational Injury Supplements to the National Agricultural Worker Survey (NAWS). Puzzlingly, past analysis of the NAWS Injury Supplement suggests that undocumented immigrants were less likely to have been injured on the job than legally-authorized farmworkers. However, this finding could be due to differential underreporting on the survey itself or due to differences in time spent working in US agriculture. This project wil develop and evaluate statistical tools which may be useful in addressing such potential sources of bias in survey-based estimates of occupational injuries and illnesses. Specifically, the project aims to:1) compare differences in self-reported occupational injury and illness counts and exposure-adjusted rates between undocumented immigrant, legal immigrant and native-born farmworkers; 2) evaluate approaches to address potential bias in survey-based estimates of occupational injury and illness rates caused by differences in reporting behavior; and 3) explore the relationships between demographic, human capital and occupational risk factors and legal immigration status differentials in occupational injury and illness rates.